ISSUE 11    July 13, 2005

HERBICIDE UPDATE

Even though most of the herbicide applications are done below are updates of registration and uses for your consideration.

Callisto (Syngenta)

Mode of action: HPPD inhibitor (27)
a.i.: mesotrione
Crops: Cuphea
Comments: ND Dept of Ag has issued a 24(c) Supplemental Label allowing use of Callisto on Cuphea for postemergence weed control. Before use, growers must sign a waiver and release from all liability and indemnification of Syngenta. For postemergence weed control, apply a single application of 3.0 oz Callisto per acre in 10-30 gallons of water by ground application. Add crop oil concentrate at 1 gallon per 100 gallons of water, and UAN at 2.5% (v/v) or AMS at 8.5 lbs per 100 gallons of water. Restrictions: Use only on non-edible oilseed varieties of cuphea. No portion of the treated field, plant, or crushed seed remaining after oil extraction may be used for human or animal feed. Apply when largest cuphea plants have two or more leaf pairs. Apply when weeds are less than 5 inches tall. Do not apply preplant incorporated or preemergence.

Glyphosate (Several)

Mode of action: EPSP synthase inhibitor (9)
a.i.: glyphosate
Crops: Various.
Comments: Syngenta has introduced New Low Foam Technology(tm) for Touchdown Total(tm) Herbicide which reduces foaming during mixing and tankfill and works by stabilizing anti-foaming agents throughout the glyphosate herbicide. During tankfill, users can cut their filling time and farmers can spray continuously without having to deal with product foaming. Glyphosate is prepared as a water-based solution while the anti-foam is made of silicone oil, which is insoluble in water and less dense than the glyphosate formulation. When the water-based Touchdown and oil are mixed together, the anti-foam droplets quickly rise to the top, separating and making anti-foam absent in the lower portions of bulk tanks. With the innovative Low Foam Technology, the anti-foam stays incorporated with the herbicide and rises very slowly through the herbicide, delaying separation for several months. The result is an improved Touchdown Total formulation with low foaming as well as easier mixing and handling.

Supplemental labels have been issued for Glyphomax XRT and Durango for postemergence applications to Roundup Ready Corn 2" Hybrids, for drop nozzle applications postemergence to corn with the Round Up Ready Gene, for preharvest and spot treatments of weeds in dry beans, dry peas, lentils and chickpeas.

A ND 24(c) SLN registration label allows use Glyphomax XRT on flax to control Canada thistle, perennial sowthistle, and other problematic weeds. The SLN registration allows ground or aerial broadcast applications of Glyphomax® XRT to flax at a maximum rate of 0.75 quart of product in a spray volume of 3 to 20 gallons of water per acre. Spot applications are also allowed. Applicators must follow all precautionary statements from the Section 3 and supplemental SLN labeling, and must have the SLN label in their possession during application. The supplemental labeling also requires a preharvest interval of at least 7 days. Straw or fodder from the treated crop may not be fed to livestock. SLN registrations were issued earlier for similar products for the same use. These include Credit® Systemic Extra Herbicide, Glyphosate 41%, Glyfos®, Touchdown®, Gly Star® Plus and RT Master® 2.

Gramoxone Inteon (Syngenta)

Mode of action: Photosystem I inhibitor (22)
a.i.: paraquat
Crops: Several uses - see label.
Comments: Registration of Gramoxone Inteon is expected soon. Uses will be similar to Gramoxone Extra and there is no difference in weed control. Differences between Gramoxone Max and Gramoxone Inteon is a change in formulation, both in amount of active ingredient and contents. Gramoxone Extra is a 3 lb ai/gal formulation and Gramoxone Inteon is a 2 lb ai/gal formulation and has reduced oral toxicity. Gramoxone Inteon contains an alginate, a natural-based shielding agent that minimizes movement into the small intestines if ingested and form a protective barrier by gelling when in contact with stomach acid. As opposed to the valeric acid which functions as a strong alerting agent in Gramoxone Extra, Gramoxone Inteon contains an leaf alcohol that smells like decaying grass to alert users not to consume. Gramoxone Inteon contains a purgative to enhance excretion and an emectic to induce emesis (vomiting).

Sequence (Syngenta)

Mode of action: EPSP synthase inhibitor (9) + Fatty acid inhibitor (15)
a.i.: 2.25 lb/gal glyphosate + 3 lb/gal s-metolachlor
Crops: Soybean
Comments: The Section 3 label covering MT and ND has been updated for SEQUENCE allowing postemergence use in RR soybeans, up to the 3rd trifoliate.

WideMatch (Dow)

Mode of action: Growth regulators (4)
a.i.: clopyralid + fluroxypyr
Crops: Small grains
Comments: EPA has approved the most recent label revisions for WideMatch, including the amended rotation interval for field peas. The least restrictive rotation interval for field peas is revised from 18 months to 10.5 months (same category as dry bean, soybean, sunflower). For rotation to field peas in 10.5 months, precipitation must be greater than 7.0 inches during the 10.5 months following application of WideMatch and greater than 5.5 inches during the June 1 through August 31 time period following application. Otherwise, rotation to field peas is recommended 18 months following application.

 

EXPRESS RESISTANT SUNFLOWER

On page 134 in the ND Weed Control Guide in the ‘Summary of New Information’ section it incorrectly mentions that DuPont has discontinued development of Express Resistant Sunflower. Pioneer and DuPont are actively working together to commercialize this technology. They anticipate, based on the projected timelines for regulatory approval in the U.S. to be demonstrating lines under ‘crop destruct’ in 2006 and launching a commercial product line in 2007 in existing high yielding NuSun Pioneer products. Pioneer will continue to breed and release new products adapted for ND with the new technology like Express Resistance.

Tolerance studies conducted at NDSU with Express on Express Resistant Sunflower show very high tolerance. 1X to 4X rates of Express with NIS, petroleum oil, MSO type oil, and basic blend + MSO oil adjuvants did not produce any injury symptoms at different sunflower growth stages.

Richard Zollinger
NDSU Extension Weed Specialist
r.zollinger@ndsu.edu


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